AFGHANISTAN -- Twenty-year-old Navy Corpsman Joshua Spencer and Marine Lance Cpl. Nathan Cordero are key players in the U.S. military's campaign to quell an uprising by Taliban and al-Qaida insurgents in this mountainous country.

Spencer, a native of Prosper, Texas, who completed his medical training at Camp Pendleton, treats local Afghans.

"A lot of elders will come up seeking help for infections and things like that," Spencer said Monday from Korengal Forward Operating Base, a mountainside post in an isolated region of Afghanistan near the border with Pakistan.

Cordero, 21, patrols an area around an isolated outpost tucked high along a steep hillside.

Spencer and Cordero are among more than 900 Marines who are working with the army and security forces in Afghanistan. They are part of a force of more than 3,000 Marines ordered into the war-torn country by Defense Secretary Robert Gates.

The troops are using humanitarian aid, as well as bombs and bullets, to stabilize this Middle East country.

Cordero, of Fontana, Calif., said the increased Marine presence in Afghanistan is helping.

"We can see that we are making a difference," he said, referring to combat and large-scale humanitarian efforts, such as food and hygiene kit distribution and medical assistance to the local population.

Col. Jeff Haynes of the III Marine Expeditionary Force based in Okinawa is directing several teams of Marines working with the Afghan Army near Bagram.

Haynes detailed his teams' efforts during a briefing for the head of Marine Corps forces throughout the Middle East, Camp Pendleton's Lt. Gen. Samuel Helland. The general is in the midst of a tour of the Middle East, visiting his commanders and troops in the field.

Haynes' teams are assigned to several bases in a mountainous region of northern Afghanistan near the Pakistani border.

Afghan National Army troops are becoming more aggressive in the fight against the Taliban and al-Qaida in the 75 days since the bulk of Haynes' forces arrived in the country.

The Afghan army recently conducted a heroin poppy eradication program around a lake, cutting into the Taliban's primary source of income. That action was significant, Haynes said.

"The point is that these guys moved and for the most part did it on their own," Haynes said in reference to the Afghans.

Haynes echoed what Marine Corps Commandant James Conway proposed last fall -- leaving Iraq and putting more forces in Afghanistan.

"Afghanistan is a better fit for us and what we do," Haynes told Helland during the briefing.

The general said he understood the desire on the part of the commandant and other Marine leaders, but warned no additional Marine troops beyond those now here should be expected.

"This will be an economy of force," the general said.

Shortly after Haynes gave his briefing, Helland and Maj. Gen. Thomas Waldhauser, commander of Camp Pendleton's 1st Marine Division, toured three bases in the rugged terrain.

At base Tagab, where a small contingent of Marines is working with several hundred Afghan troops, two Afghan commanders described recent fighting in the area.

Sitting inside a small, wooden room, the commanders said the recent poppy eradication in the area removed about 70 percent of the local crop.

Speaking through an interpreter, they said about 16 different enemy groups were operating in the area. The 500 insurgents were armed with AK-47 assault rifles and rockets but hadn't attacked any of the Afghan bases.

"Thank God they did not do any attacks on us," said an Afghan general, whose name was not released.

Local residents are increasingly reporting planned attacks, the Afghans said, because they are tired of the violence and intimidation waged by the Taliban.

During a stop at Cordero's outpost, Marines reported frequent attacks, mostly small-arms fire and rocket-propelled grenades.

Cordero said he was hit by a round during an operation on April 12.

Displaying the hole where the bullet struck, Cordero described how the round struck the casing for a grenade he was carrying on his chest. The bullet stopped there, combusting the grenade charge and slightly burning the 21-year-old's neck.

"I was laughing at first, but then I got mad at myself because I got hit," he said.

Spencer's outpost also has taken its share if gunfire.

"We usually take small arms fire every couple of days," said Spencer, who is able to call home every other day and check on his older brother who is serving in Iraq.

"My mom is really worried about us," he said. "But we're both doing just fine."

Spencer said he joined the Navy because he was looking for a more exciting way to apply the emergency medical technician training he undertook before joining the service.

"I just wanted to do something more," he said. "And this is sure different."

Contact staff writer Mark Walker at (760) 740-3529 or mlwalker@nctimes.com.